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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Grid2tm1Mim
targeted mutation 1, Masayoshi Mishina
MGI:2178052
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Grid2tm1Mim/Grid2tm1Mim B6.Cg-Grid2tm1Mim MGI:4943910
hm2
Grid2tm1Mim/Grid2tm1Mim involves: C57BL/6 * CBA MGI:3699325


Genotype
MGI:4943910
hm1
Allelic
Composition
Grid2tm1Mim/Grid2tm1Mim
Genetic
Background
B6.Cg-Grid2tm1Mim
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Grid2tm1Mim mutation (4 available); any Grid2 mutation (85 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• reacquisition and retention of the conditioned response are also impaired (J:89436)
• mice are severely impaired with acquisition of the earlier, nonstartle component of response as well as of the adaptively timed response (J:89436)
• however, acquisition of the trace eye blink conditioning response is similar to controls (J:89436)
• acquisition of delay eye blink conditioning is severely impaired when the conditioned stimulus and unconditioned stimulus have temporal overlap but not when they don't overlap (J:107990)
• exhibit significantly larger phase lag at all frequencies examined
• do not display OKR adaptation in response to continuous oscillation of a screen at 0.4 Hz +/- 1.8 degrees unlike wild-type mice
• flocculectomy does not significantly alter the abnormal OKR; however, lesions of the dorsal cap olivary nuclei neurons do reduce OKR abnormalities
• exhibit higher VOR dark (VORD) gains, lower VOR light with earth stationary visual stimuli (VORL) gains and higher VOR light with synchronously moving visual stimuli (VORS) gains compared to wild-type mice
• exhibit higher VORD gains at the lowest amplitude tested with progressively lower gains as the angular amplitude of head rotation increases, the opposite of what is seen in wild-type or Grid2Lc homozygous mice
• VORD phase differs from wild-type and Grid2Lc homozygous mice at rotations frequencies higher and lower than 0.4 Hz
• VORS gains are larger to VORL gains, the opposite of what is seen in wild-type mice
• VOR gain is nearly constant across all conditions, regardless of the relationship between screen and head rotation, and lower than VORD gain, unlike in wild-type mice
• adaptive changes to VORD gains from training are not seen, unlike in wild-type mice
• flocculectomy does not significantly alter the abnormal VORD and VORL gains; however, lesions of the dorsal cap olivary nuclei neurons do reduce VOR abnormalities
• fall off a stationary rod or rotarod earlier than wild-type controls and mice homozygous for Grid2Lc
• the eye moves irregularly and continuously (J:97010)
• spectral analysis detects spontaneous eye movement at low and high frequencies (J:97010)
• spontaneous eye movement is increased in both light and dark conditions although results indicate that visual inputs contribute to the increased movement (J:97010)
• bilateral flocculectomy decreased the fast component of spontaneous eye movement, abolished the peak around 10 Hz, and decreased the peak around 1 Hz in the power spectrum (J:97010)
• a correlation is seen between complex spikes and clustered firings and the spontaneous eye movement (J:97010)
• involuntary oscillatory eye movement (J:101081)

nervous system
• Purkinje cells sometimes show repetitive firing of apparent simple spikes with short intervals (clustered firing)
• time courses of complex spikes are variable
• autocorrelation histograms for apparent simple spikes show a peak at a very short lag time and multiple additional peaks
• the periodicity of about 10 Hz appears to be attributable to the clustered firings
• clustered firing is evoked by climbing fiber activation
• a correlation is seen between complex spikes and clustered firings and the spontaneous eye movement

vision/eye
• the eye moves irregularly and continuously (J:97010)
• spectral analysis detects spontaneous eye movement at low and high frequencies (J:97010)
• spontaneous eye movement is increased in both light and dark conditions although results indicate that visual inputs contribute to the increased movement (J:97010)
• bilateral flocculectomy decreased the fast component of spontaneous eye movement, abolished the peak around 10 Hz, and decreased the peak around 1 Hz in the power spectrum (J:97010)
• a correlation is seen between complex spikes and clustered firings and the spontaneous eye movement (J:97010)
• involuntary oscillatory eye movement (J:101081)

hearing/vestibular/ear
• exhibit higher VOR dark (VORD) gains, lower VOR light with earth stationary visual stimuli (VORL) gains and higher VOR light with synchronously moving visual stimuli (VORS) gains compared to wild-type mice
• exhibit higher VORD gains at the lowest amplitude tested with progressively lower gains as the angular amplitude of head rotation increases, the opposite of what is seen in wild-type or Grid2Lc homozygous mice
• VORD phase differs from wild-type and Grid2Lc homozygous mice at rotations frequencies higher and lower than 0.4 Hz
• VORS gains are larger to VORL gains, the opposite of what is seen in wild-type mice
• VOR gain is nearly constant across all conditions, regardless of the relationship between screen and head rotation, and lower than VORD gain, unlike in wild-type mice
• adaptive changes to VORD gains from training are not seen, unlike in wild-type mice
• flocculectomy does not significantly alter the abnormal VORD and VORL gains; however, lesions of the dorsal cap olivary nuclei neurons do reduce VOR abnormalities




Genotype
MGI:3699325
hm2
Allelic
Composition
Grid2tm1Mim/Grid2tm1Mim
Genetic
Background
involves: C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Grid2tm1Mim mutation (4 available); any Grid2 mutation (85 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• mice are slower to assume a swimming posture when dropped into water by a roll rotation load
• following injection of sodium arsanilate into the right middle ear mice show a slower recovery of the righting response with some mice unable to stop rotation even 28 days after injection
• moderate locomotor ataxia is noticed by P12
• in a running along an elevated runway task, homozygotes walk slowly along the runway with many slips, unlike wild-type mice that quickly run through with few slips; there is some improvement over time
• in a rotating rod task, the retention time of homozygotes is much shorter, although some improvement occurs over time
• following injection of sodium arsanilate into the right middle ear mice show a more severe head tilt compared to controls
• prior to sodium arsanilate injection no head tilt is seen
• often walk with tottering steps and sometimes scramble to their hindlimbs
• when rearing, homozygotes often pitch and roll due to poor balance
• total rearing time is shorter than that of wild-type
• at P26-28, show significantly reduced horizontal activity measured as total walking distances
• show a significant difference in total running time with high speeds

nervous system
• synaptic contacts with postsynaptic densities are sparse on the dendritic spines of Purkinje cells and correspondingly, spines without synaptic contacts but surrounded by sheets of Bergmann glial cells are more abundant than in wild-type
• climbing fibers extend up to a more superficial regions of the molecular layer
• exhibit multiple innervation of Purkinje cells by climbing fibers (J:24975)
• some spines posses high electron density, like postsynaptic membranes, but miss the synaptic contact with parallel fibers, indicating that synapse formation between parallel fibers and Purkinje cells is impaired (J:24975)
• most cells are innervated by multiple climbing fibers (J:73385)
• climbing fibers innervate more distal portions of the Purkinje cells (J:73385)
• synapse formation between parallel fibers and Purkinje cells is impaired
• long-term depression of parallel fiber-Purkinje cell synaptic transmission is impaired, indicating impaired cerebellar LTD (J:24975)
• the amplitudes of Purkinje cell spontaneous compound post synaptic currents do not increase after conditioning stimulus unlike in wild-type controls indicating a failure of rebound potentiation (J:109764)
• direct depolarization of Purkinje cells also fails to induce rebound potentiation (J:109764)
• results indicate GABAergic inhibition in the molecular layer is increased compared to wild-type controls
• bicuculline induced increase in the depolarized area is increased compared to wild-type controls
• increase in the incidence of climbing fiber induced excitatory postsynaptic currents (CF-EPSCs) with more than one discrete step in mutant Purkinje cells compared to wild-type cells
• each CF-EPSC displays clear pair pulse depression to a similar or greater extent than that of wild-type currents
• Purkinje cells innervated by multiple climbing fibers display two populations of CF-EPSCs, one fast with a large amplitude (similar to wild-type) and one slow with a small amplitude (not seen in wild-type cells)
• slow CF-EPSCs become evident during the second postnatal week
• average mIPSC amplitude of Purkinje cells is increased compared to wild-type controls
• however, no difference is seen in isolated cultured Purkinje cells that lack climbing fiber innervation
• cultured Purkinje cells show slight potentiation under conditions that induce depression in cells from wild-type mice

homeostasis/metabolism
• following injection of sodium arsanilate into the right middle ear mice show a more severe head tilt and slower recovery of the righting response compared to controls





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last database update
03/19/2024
MGI 6.23
The Jackson Laboratory